Energy translating platforms incorporated into footwear for enhancing linear momentum

ABSTRACT

The present invention provides soles or platforms incorporated into footwear, preferably athletic footwear, designed to promote a more efficient running technique by an energy-translating sole comprising one or more foot-strike member, angular displacement member and balance-thrust member, as well as other conventional features. Systems and methods of the present invention promote more efficient running technique by facilitating foot-strike to occur at a point under and behind the runner&#39;s center of gravity. This may be accomplished, for example, by a foot-strike member, angular displacement member and balance-thrust member working cooperatively to displace the runner&#39;s center of gravity and translate gravitational, inertial and ground reaction forces, as well as muscular tension forces, into linear momentum.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of co-pending U.S.patent application Ser. No. 10/045,299, filed on Oct. 23, 2001, whichclaims priority to provisional application No. 60/242,742, filed on Oct.23, 2000. The priority of the prior applications is expressly claimedand their disclosures are hereby incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to athletic shoe technology. Moreparticularly, it relates to systems and methods for various forms ofenergy-translating soles, or platforms, which are incorporated intofootwear and are designed to more effectively transfer gravitational,inertial and ground reaction forces into linear momentum therebypromoting a more efficient running technique.

[0004] 2. Description of the Related Art

[0005] Athletic shoe technology has undergone a revolution over the pastthirty years, particularly in regards to improvements in running shoes,both for the professional and casual user. In general, the majority ofadvancements in running shoe technology have largely centered aroundsupport, shock absorption and energy efficiency. For example, U.S. Pat.No. 5,909,948 describes an athletic shoe sole having a lateral stabilityelement to provide improved lateral support during heel-strike. U.S.Pat. Nos. 5,247,742 and 5,297,349 describe a cushioning sole forathletic shoes having a pronation control device incorporated into themidsole in order to increase the resistance to compression of themidsole from the lateral side to a maximum along the medial side, andU.S. Pat. No. 5,987,779 describes an athletic shoe having an inflatabletongue or bladder for a more secure fit.

[0006] A major focus in athletic shoe technology has centered on shockabsorption. A number of patents describe various systems for shockabsorption, such as air channels, miniature pumps, hydraulic systems,gas-filled bladders, elastomeric foam elements, pneumatic inflationdevices and spring elements. The following are illustrative of suchtechnologies: U.S. Pat. No. 5,598,645, U.S. Pat. No. 4,535,553, U.S.Pat. No. 5,325,964, U.S. Pat. No. 5,353,523, U.S. Pat. No. 5,839,209,U.S. Pat. No. 5,983,529 and U.S. Pat. No. 4,763,426.

[0007] Embodiments of the present invention are distinct from theathletic shoe technologies pertaining to additional support or shockabsorption described above in that systems and methods of the presentinvention focus on locomotion efficiency.

[0008] There have been several shoe systems related to increasing energyefficiency during running, such as U.S. Pat. No. 4,358,902, whichdescribes a thrust-producing shoe comprising a sole having fluid-filledcavities located in the heel and metatarsal portions with passagewaysinterconnecting the fluid-filled cavities. As the heel cavity iscompressed, fluid is forced through the passageways into the metatarsalcavities thereby providing shock absorption and forward thrust in theheel and metatarsal area.

[0009] U.S. Pat. No. 4,030,213 discloses a sporting shoe having anauxiliary sole member that is relatively thick under the toe portion andits outer surface is curved to form nearly a half circle at the forwardextremity of the toe section and the rearward extremity at the ball ofthe foot is relatively flat. An additional embodiment describes aplurality of recesses within the sole of the shoe for housing a numberof coil springs.

[0010] U.S. Pat. No. 4,506,460 describes a spring moderator for articlesof footwear, wherein a high modulus moderator is positioned beneath theheel or forefoot with a cushioning medium beneath the moderator. Thespring moderator operates to absorb, redistribute and store the energyof localized loads.

[0011] U.S. Pat. No. 4,936,030 provides an energy efficient running shoehaving an energy-transmission mechanism in the heel portion of the soleto transmit the mechanical energy of heel impact to the storage/thrustmechanism in the front sloe portion, where it is stored and releasedduring thrust. A number of embodiments are described havingsophisticated systems employing lever arms, coils springs, hydraulicassemblies and the like for capturing and transferring mechanicalenergy.

[0012] U.S. Pat. No. 4,949,476 discloses a running shoe having a hardfront sole for retaining gripping elements and, from the ball to theshank of the foot, an upwardly extending support cup on the outside ofthe shoe upper. The front sole extends into the shank portion of theshoe and covers a support wedge member. The wedge member extends fromthe ball of the foot to the shank and is progressively thicker towardsthe rear portion of the shoe. The wedge shaped member causes the foot tobe brought into an extended position for emphasizing contact with theground with the front outside ball region of the foot. Thisconfiguration serves to increase running efficiency by keeping the heelin an elevated position, which is the preferred attitude duringsprinting.

[0013] U.S. Pat. No. 5,586,398 provides an article of footwear for moreefficient running and walking wherein the contour of the outer sole atthe heel is formed at a dihedral angle to the medial/forefoot portionsin order to delay the instant of initial contact and thereby allow alonger length of foot flight and correspondingly longer stride length.An additional embodiment provides for friction management throughmaterials selection, surface coatings, or surface treatments designed toaffect friction across one or more interfaces between foot plantarsurface and shoe insole.

[0014] U.S. Pat. No. 5,647,145 describes a sculptured sole for anathletic shoe comprising a plurality of forward support pads, rearwardsupport lands, a layer of flexible resilient elastic materialinterconnecting various components, as well as a plurality of channels,grooves, slots and the like, which complement the natural flexingactions of the muscles of the heel, metatarsals and toes of the foot.

[0015] U.S. Pat. No. 5,680,714 discloses a trampoline effect athleticshoe having elastic return strips running across the sole of the shoeand supported above the bottom surface in a gap between the outsole andinsole.

[0016] U.S. Pat. No. 5,829,172 relates to shoe soles of running shoes,particularly for 100 m sprints and the like. The object of the inventionis to prevent the heel from touching the ground during running andthereby prevent a decrease in running efficiency. The sole comprises athickly formed forefoot section for receiving spikes. A Reinforcingmember provided in the ball region of the foot is integrated withreward-projecting medial and lateral ribs to form a wedge-shaped planeextending toward the heel. Medial and lateral ribs and reinforcingmember form a wedge-shaped inclined plane extending form the ball to thearch of the foot, which serves to maintain the weight distribution ofthe runner over the ball of the foot and hold the heel of the foot in anelevated position.

[0017] U.S. Pat. No. 5,743,028 describes a spring-air shock absorptionand energy return device for shoes in which a shoe heel insert isprovided having a heel-shaped outer spring mechanism which serves as aninternal spring housing wherein a plurality of compression springs areretained, and wherein the entire unit is filled with a pressurized gasand hermetically sealed.

[0018] U.S. Pat. No. 5,87,568 pertains to an athletic shoe wherein thesole has a rounded heel strike area and gently curved bottom thatgradually thins towards the toe section to permit the runner to rollsmoothly forward from the initial heel strike. Additional embodimentsfurther provide for a shock-absorbing insert in the heel section.

[0019] U.S. Pat. No. 5,937,544 provides athletic footwear wherein thesole includes a foundation layer of semi-flexible material attached tothe upper and defining a plurality of stretch chambers, a stretch layerand a thruster layer attached to the stretch layer such thatinteractions can occur between the foundation layer, stretch layer andthruster layer in response to compressive forces applied thereto so asto convert and temporarily store energy applied to regions of the soleby wearer's foot into mechanical stretching of the portions of thestretch layer into stretch chambers. The stored applied energy isthereafter retrieved in the form of rebound of the stretched portions ofthe stretch layer and portions of the thruster layer.

[0020] U.S. Pat. No. 6,006,449 and U.S. Pat. No. 6,009,636 relates tofootwear having various forms of spring assemblies incorporated into thesole, which serve to absorb shock and transfer energy.

[0021] The foregoing and other known prior art have fundamentaldisadvantages in that they are not directed at improving efficiency bysynchronizing the three basic phases of the human running cycle, seenillustrated in FIGS. 6A-6C with elements on the shoe that optimizemomentum, efficiency, and fluidity of motion through the cycle. Forexample, prior art shoes place the wearer in a plantigrade stance, asshown in FIG. 7. Generally, a plantigrade stance is created between thebalance of two points: one at the calcaneous and the other at themetatarsal/phalanges joints. Relative to the digitigrade stance providedthrough the novel embodiments of the present invention described below,plantigrade shoe systems are inefficient in that in subject the wearerof the shoe systems to greater breaking forces during running cycles.

[0022] Rather than hydraulic or pneumatic systems; mechanical springand/or lever assemblies; resilient elastic bands; alteration of theheel-strike region; or reinforcing structures to maintain the heel in anelevated position, the present invention provides systems and methodsthat promote efficient running technique by providing a sole comprisinga specially designed foot-strike member and balance-thrust member, whichare integrated with a unique pivot and balance structure that displacesthe wearer's center of gravity when running, thereby transferringgravitational, inertial and ground reaction forces, as well as musculartension generation into linear momentum. Systems and methods of thepresent invention are an advance in the field of athletic shoetechnology by providing a specialized sole design for redirecting theforces encountered during running into linear momentum, while reducingthe shock and trauma to the body. The present invention provides novelfootwear and components thereof for achieving a more efficient centeringof mass that helps improve transfer of momentum energy to a stableplatform for propulsion during toe-off (propulsion) phase of gait.

SUMMARY OF THE INVENTION

[0023] Systems and methods of the present invention provideenergy-translating soles, or platforms, for footwear, preferablyathletic footwear, designed to promote a more efficient runningtechnique. In one aspect, promoting a more efficient running techniqueis facilitated by an energy-translating sole comprising one or more ofthe following features: at least one foot-strike member, one or moreangular displacement members and at least one balance-thrust member, aswell as other conventional features.

[0024] In another aspect, systems and methods of the present inventionpromote more efficient running technique by facilitating foot-strike tooccur at a point under and behind the runner's center of gravity. Thisis accomplished by the foot-strike member, angular displacement memberand balance-thrust member working cooperatively to displace the runner'scenter of gravity and translate gravitational, inertial and groundreaction forces, as well as muscular tension forces, into linearmomentum.

[0025] In a further aspect, systems and methods of the present inventionprovide one or more foot-strike members, which may be situated in anylocation along the longitudinal axis (X axis) of the energy-translatingsole with a front zone extending into the forefoot area and a rear zoneoptionally extending into the heel section. Foot-strike member mayencompass the entire heel to forefoot sections, and/or any region therebetween. The medial and lateral margins of foot-strike member maygenerally follow the natural contours of the foot, and in embodimentswherein foot-strike member extends rearwardly to the heel, foot-strikemember generally follows the contour of the heel.

[0026] In yet another aspect, angular displacement member is generallylocated forward of foot-strike member, and is generally positioned inthe forefoot or metatarsal area of the foot. The front margins ofangular displacement member may extend well into the toe section of solewith the rear margin optionally extending along the longitudinal axiswell into the arch section of the sole. In a related aspect, variousembodiments employ specially configured angular displacement members tosuit particular running needs.

[0027] In another aspect, angular displacement member may have anynumber and/or sort of traction-related features, such as, but notlimited to, grooves, channels, ribs, points, raised projections of anysort, and the like.

[0028] In still yet another aspect, angular displacement member isgeometrically designed to provide a pivoting zone, preferably runningtransversely in the Z-axis between medial and lateral margins. Pivotzone may be located at or near the sesamoidal line along thelongitudinal axis (X-axis) within angular displacement member dependingupon the particular embodiment. Preferred embodiments of the presentinvention have pivoting zone encompassing the metatarsal region of thefoot at or near the sesamoid bones of the first metatarsal head.

[0029] In a further aspect, systems and methods of the present inventionprovide one or more balance-thrust members, which generally encompassthe toe section of the sole. Alternative embodiments may provide atleast one balance-thrust member further comprising a plurality oftraction facilitating members, such as spikes, teeth, ridges, groovesand the like. Medial and lateral margins of balance-thrust membergenerally follow the natural contours of the anatomical features of thefoot, but the overall configuration and orientation of balance-thrustmember varies with each particular embodiment.

[0030] In yet another aspect, the present invention provides a pluralityof embodiments specifically designed for different running needs, whichis partially dictated by the speed and distance involved. Eachparticular embodiment has a unique configuration and orientation offoot-strike member, angular displacement member and balance-thrustmembers to accommodate the unique biomechanical requirements of varioustypes of running.

[0031] Other aspects of the present invention provide systems andmethods to effectively displace the runner's center of gravity andtranslate gravitational, inertial and ground reaction forces into linearmomentum. In another aspect, the present invention provides a platformthat provides a rotational base for dissipating the shock of footstrike, thereby providing a more comfortable running shoe, which helpsreduce the risk of injury associated with forceful foot strike.

[0032] These and other objects, advantages, and features of thisinvention will become apparent upon review of the followingspecification and accompanying drawings.

BRIEF SUMMARY OF THE DRAWINGS

[0033]FIG. 1A shows a conventional shoe illustrating general features ofa running shoe typically found in the prior art.

[0034]FIG. 1B is a lateral perspective of the skeletal system of thehuman foot depicting the various anatomical features in relation toconventional footwear.

[0035]FIG. 2 shows a stylized plantar view of one embodiment of anathletic shoe sole of the present invention in spatial reference to thehuman foot.

[0036]FIG. 3 is a cross-sectional side view of an athletic shoeemploying systems of the present invention.

[0037]FIG. 4A is an alternative embodiment designed for distancerunning.

[0038]FIG. 4B is an additional embodiment designed for mid-distancerunning, such as a 1500 m race.

[0039]FIG. 4C shows yet another embodiment specifically designed forshort-distance sprints, such as a 100 m race.

[0040] FIGS. 5A-D illustrate the correlation of foot cycle, that is fromfoot-strike to angular displacement point, to angle 2 of redirection ofenergy into maximum linear momentum for and embodiment forshort-distance sprints, such as a 100 m race (5A), mid-to-long distancesprints, such as a 800 m race (5B), mid-distance running, such as a1,500 m race (5C) and long-distance running, such as jogging (5D).

[0041] FIGS. 6A-C illustrate three basic phases of the human runningcycle.

[0042]FIG. 7 illustrates the center of mass of a runner achieved usingconventional footwear versus the center of mass achieved of a runnerusing footwear according to the present invention.

[0043]FIG. 8 is a top view of the plantar surface of a sole unitaccording to the present invention.

[0044]FIG. 9 is the sectional view of the sole unit of FIG. 8 takenalong line 9-9.

[0045]FIG. 10 is a top view of the plantar surface of a sole unitaccording to the present invention.

[0046]FIG. 11 is the sectional view of the sole unit of FIG. 10 takenalong line 11-11.

[0047]FIG. 12 is a top view of the plantar surface of a sole unitaccording to the present invention.

[0048]FIG. 13 is the sectional view of the sole unit of FIG. 12 takenalong line 13-13.

[0049]FIG. 14 is a top view of the plantar surface of a sole unitaccording to the present invention.

[0050]FIG. 15 is the sectional view of the sole unit of FIG. 14 takenalong line 15-15.

[0051]FIG. 16 is a top view of the plantar surface of a sole unitaccording to the present invention.

[0052]FIG. 17 is the sectional view of the sole unit of FIG. 16 takenalong line 17-17.

[0053]FIG. 18 illustrates the relationship of certain anatomical partsof the foot to a sole unit according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0054] It is believed that the advantages of the present invention arisefrom a more efficient, relative forward centering of mass of the runnerduring the running cycle. In contrast to the inherently inefficientcentering of mass of conventional running shoes that places runners in aplantigrade stance during the foot-contact phase of the running cycle,the present invention places runners in a digitigrade stance that moreoptimally moves the center of mass of the wearer forward throughrepeated running cycles, as generally indicated in FIG. 7. Moving thecenter of mass forward of the position achieved in the plantigradestance allows the counter-balance thruster unit to create a stableforefoot platform, enhancing propulsion, and a smoother transition fromfoot-strike to toe-off. The present invention also provides a platformfor the foot that provides a rotational base for dissipating the shockof foot strike, thereby providing a more comfortable running shoe, whichhelps reduce the risk of injury associated with forceful foot strike.

[0055] The embodiments of the present invention all relate to a soleunit, such as sole unit 1211, for use in an item of footwear. In generalterms, a sole unit is the whole or part of any portion of a shoe that isdisposed between a foot of the wearer and the ground. More specifically,the sole unit portion may be the whole or part of the outsole, midsole,insole or combinations thereof. It may be a footwear insert, such as anorthotic. Specific example embodiments of sole units are described inmore detail below.

[0056] As noted above, the novel sole units of the present invention areadapted to place the wearer in a “digitigrade” stance. Generally, twopoints in the forefoot area define a “sesamoidal line”: one at about themetatarsal/phalanges joints and one at about a more distal (forward)area. In the digitigrade stance, the sole unit elevates themetatarsal/phalanges joints, including the sesamoid points as shown inFIG. 18. The degree of elevation has a direct relation to therotation/displacement of the wearer's center of mass: the higher theelevation (within anatomical/biomechanical limits), the greater therotation/displacement, which correspondingly allows smoother transitionof mechanics from foot-strike to toe-off. The rotation possible with adigitigrade stance also spreads the force of foot strike over the timeand surface over which the rotation occurs, thereby dissipating impactforces relative to conventional shoes, which do not have a mechanism fora digitigrade stance and rotation/counterbalance, as described below.

[0057]FIG. 18 shows the general positioning of the sole unit relative toa foot of a wearer. It can be seen that the heel 3 of the foot iselevated relative to the sesamoidal region 5. For certain shoes such asrunning shoes, street, shoe, etc. it will be desirable to provide anin-fill material under some or all of the raised area to support thefoot. The in-fill could be in the form of a cushioning material and/oroutsole, for example. On the other hand, in the case of a track shoe,where a forefoot foot strike dominants during Use, little or no in-fillneed be provided.

[0058] In embodiments of the present invention, an angular displacementmember in the area of the metatarsal/phalanges joints achieves thedigitigrade stance and a balance-thrust member in a more forward area.In one possible embodiment, the digitigrade stance is based at least inpart on a position of balance about a line—“the sesamoidline”—substantially defined by the sesamoid apparatus and the head ofthe fifth metatarsal. In the various embodiments of sole units describedherein, the sole units are adapted to allow the wearer's foot to pivotforward or aft around such a line.

[0059] The balance-thrust member is a counterbalance or stop to helpcontrol the forward motion and balance of the wearer, i.e., help keepthe wearer from falling forward following the angular forward pivot ofthe angular displacement member. In this regard, the balance-thrustmember may be provided at one or more points forward of the metatarsalbones, preferably at points in a line—the “balance-thrustline—substantially defined by the first distal phalange to about atleast the third distal phalange.

[0060] Accordingly, a digitigrade support system according to thepresent invention: (1) enables the center of mass to move more forwardlyduring the propulsive phase relative to the position of center of masssustained by a plantigrade type of support system during the same phase,as illustrated in FIG. 7; or (2) enables the center of mass to moveforward more quickly than it would move in a plantigrade support system.In either case, there is direct influence on the forwardrotation/displacement of the center of mass, and the digitigrade systemhelps reduce breaking forces, resulting in greater inertial forces.

[0061] While the invention may be embodied in different forms to achievemore optimal centering of mass, the specific embodiments shown in thefigures and described herein are presented with the understanding thatthey are exemplary of the principles of the invention and are notintended to limit the invention to that specifically illustrated anddescribed herein. FIG. 1A shows a generic form of footwear comprising anupper, indicated generally as 10, and a sole unit which generally maycomprise (i) a midsole for energy absorption and/or return; (ii) anoutsole material for surface contact and abrasion resistance and/ortraction; or (iii) a single unit providing such midsole or outsolefunctions. For example, the sole unit shown in FIG. 1A includes amidsole 12, an outsole 114 and an insole 16 on the interior lowersurface of the footwear. The sole unit can cover some or all of the areaof the supported foot.

[0062] As is well known in the art, the sole unit may include resilientelements that provide cushioning against shock. They may also be of anature that provides energy return (in essence, spring) upon impact. Forconvenience, unless otherwise expressly or contextually indicated,“resilient element” refers to an element with either energy absorptionand/or return functionality. One or more resilient elements may beincluded in a sole unit at locations where cushioning may be needed. Forexample, the rearfoot portion of the sole unit would typically requirecushioning, and resilient element may be located there. Similarly,forefoot section may include one or more resilient elements.

[0063] The shoe illustrated in FIG. 1A has a conventional shoelace 18engaged in eyelets 20. Upper 10 is partially split at the central, topportion of the footwear wherein lies some form of closure system 24,such as a conventional tongue. Collar 22 is provided to support the footand/or ankle. Generally speaking, conventional shoes may be divided intoheel (A), arch (B), ball or forefoot (C) and toe (D) regions. Theseelements of the footwear illustrated in FIG. 1A are generallyconventional. Athletic shoes of the present invention comprise suchconventional features, as well as others in conjunction with a speciallydesigned sole system. FIG. 1B is a lateral perspective of the skeletalsystem of the human foot wherein the heel (A), arch (B), ball (C) andtoe (D) regions of a conventional shoe align, in a general sense, withthe anatomical structures depicted therein.

[0064] FIGS. 2-3 show a stylized plantar view of one embodiment of anathletic shoe sole, namely an energy-translating sole 100 of the presentinvention, in spatial reference to the human foot. FIG. 3 depicts across-sectional side view of the same embodiment. In certain broadaspects, systems and methods of the present invention provide anenergy-translating sole unit, that is incorporated into shoes,preferably athletic shoes, including one or more of the followingfeatures: at least one foot-strike member 102, one or more angulardisplacement members 104, with its apex falling at or near the sesamoidapparatus medially and extending under lesser metatarsal headslaterally, and at least one balance-thrust member 106. As illustrated,there may be considerable overlap of the various members 102, 104, 106,but in alternative embodiments, members 102, 104, 106, may notnecessarily have appreciable overlap. In general, systems and methods ofthe present invention promote more efficient running technique byfacilitating foot-strike to occur at a point under and behind therunner's center of gravity. Foot-strike member 102, angular displacementmember 104, and balance-thrust member 106 work cooperatively, creating astable forefoot platform and smoother transition from footstrike totoe-off, and to displace the runner's center of gravity and translategravitational, inertial and ground reaction forces, as well as musculartension forces, into linear momentum.

[0065] As will be described in greater detail below, systems and methodsof the present invention provide a plurality of embodiments specificallydesigned for different running needs, which is partially dictated by thespeed and distance involved. The particular embodiment depicted in FIGS.2 and 3 comprises footwear designed for running a mid-to-long distancesprint, such as a 400 m race. It is understood that the embodimentdepicted in FIGS. 2 and 3 are merely illustrative of the generalprinciples of the present invention and are not meant to be limiting inany respect.

[0066] Foot-strike member 102 is generally made of any conventionaldense, semi-deformable, wear resistant material, such as syntheticpolymers and plastics of any sort, having sufficient compliance andresiliency features to adequately absorb a relative portion of impactforces imparted to the shoe and body of the runner upon initial contactwith a supporting surface. Various embodiments of the present inventionmay employ materials that are more suitable for that particularapplication. For example, an embodiment for distance running may utilizea material for foot-strike member 102 having greater indices ofcompliancy and resiliency than an embodiment for sprinting. Foot-strikemember 102 comprises a front zone 112 (FIG. 3) extending towards toesection 126 (FIG. 2) and a rear zone 114 extending towards heel section120. In preferred embodiments, front zone of foot-strike member 112 isarcuately formed to follow the natural anatomical features of the foot,but alternative embodiments also include additional configurations andfoot-strike member rear zone 114 generally follows the anatomicalmargins of the foot, such as the arch and heel. Foot-strike member 102may be situated in any location along the longitudinal axis (X axis) ofsole 100 with front zone 112 extending into forefoot section 124 rearzone 114 extending into heel section 120 and may encompass the entireheel 120 to forefoot 124 sections, and/or any region there between. Themedial 108 and lateral 110 margins of foot-strike member 102 generallyfollow the natural contours of the foot, and in embodiments whereinfoot-strike member 102 extends rearwardly to the heel, foot-strikemember 102 generally follows the contour of the heel.

[0067] Foot-strike member 102 may be of a singular uniform moldedcomposition or alternatively, be provided in a layered or compositeconfiguration. Plantar surface 116 of foot-strike member 102 may beintegral with and/or adjacent to any conventional outsole having anynumber and/or type of traction-related features, such as, but notlimited to, grooves, channels, ribs, points, raised projections of anysort, and the like. Furthermore, foot-strike member 102 may furthercomprise any conventional pneumatic and/or hydraulic cells, bladders,chambers and the like to further facilitate and control shockabsorption.

[0068] The configuration, dimensions and preferred constructionmaterials of foot-strike member 102, as well as angular displacementmember 104 and balance-thrust member 106, is largely dependent upon theparticular embodiment. The embodiment presented in FIGS. 2 and 3 showfoot-strike member 102 having a generalized elliptical form having athickness ranging from 0.5 to 10 cm, with front zone 112 taperingtowards, and transitioning with and/or into angular displacement member104 and rear zone 114 tapering and transitioning with and/or into one ormore support bases 158. Naturally, the tapered ends of foot-strikemember may fall outside the provided ranges. Support base 158 may be maybe integral with and/or adjacent to any conventional outsole having anynumber and/or type of traction-related features, such as, but notlimited to, grooves, channels, ribs, points, raised projections of anysort, and the like.

[0069] Angular displacement member 104 is located forward, towardsforefoot 124 and toe regions 126, of foot-strike member and is generallypositioned in the forefoot or metatarsal area 124 of the foot. Frontzone 128 of angular displacement member 104 is generally arcuatelydesigned and may extend well into toe section 126 of sole 100 and rearzone 130 of angular displacement member 104 may extend along thelongitudinal axis well into arch section 122 of sole 100. Alternativeembodiments envision angular displacement member 104 being more compact,that is, encompassing less surface area, and more discreetly positionedover the metatarsal and/or metatarsal-phalanges areas of the foot.Dorsal surface 134 of angular displacement member 104 is integrated withor fixedly adhered to support base 158. Plantar surface 132 of rear zone130 of angular displacement member 104 is fixedly integrated with and/oradhered to dorsal surface 118 of front tapering zone 112 of foot-strikemember 102, such that a relatively smooth transition between foot-strike102 and angular displacement 104 members is achieved and a strong,permanent bond or integral component is provided. In preferredembodiments, plantar surface 132 of angular displacement member 104 mayhave any number and/or sort of traction-related features, such as, butnot limited to, grooves, channels, ribs, points, raised projections ofany sort, and the like. Medial 136 and lateral 138 margins of angulardisplacement member 104 generally follow the natural anatomical profileof the foot and, preferably, flow smoothly into respective medial 108and lateral 110 margins of foot-strike member 102.

[0070] Angular displacement member 104 is geometrically designed toprovide a pivoting zone 140, preferably running transversely in theZ-axis between medial 136 and lateral 138 margins. Preferred embodimentsof the present invention have pivoting zone 140 in the forefoot 124region, and more preferably encompassing the metatarsal region of thefoot at or near the sesamoidal line. Pivot zone 140 may be locatedanywhere along the longitudinal axis (X-axis) within angulardisplacement member 104 depending upon the particular embodiment. Pivotzone 140 may be variously shaped, but in preferred embodiments, isarcuately formed to follow the natural curvature and anatomicalstructures of the foot, such as, but not limited to, themetatarsal-phalanges articulations, as well as accommodate and exploitthe natural lateral to medial rolling of the foot during running.Systems and methods of the present invention are designed to promotemore efficient running technique by facilitating foot-strike to occur ata point under and behind the runner's center of gravity. Foot-strikemember 102, angular displacement member 104, and balance-thrust member106 work cooperatively, creating a stable forefoot platform and smoothertransition from footstrike to toe-off, and to displace the runner'scenter of gravity and translate gravitational, inertial and groundreaction forces, as well as muscular tension forces into linearmomentum.

[0071] Front zone of angular displacement member 128 is integral with,and/or fixedly adhered to, rear section 148 of balance-thrust member 106in an overlapping or abutting manner. Balance-thrust member 106 islocated forward (i.e., towards toe section 126) of angular displacementmember 104 and generally encompasses the front part of forefoot section124 and all of toe section 126 of sole 100. Depending upon theparticular embodiment, balance-thrust member 106 may be formed ofsemi-deformable material or essentially non-deformable material, but ingeneral, comprises a material having relatively less compliancy andresiliency than that of foot-strike member 102, such as conventionalsynthetic polymers and/or plastics, such that significant levels ofkinetic and mechanical energy are not overly dampened by deformation ofthe material. In select embodiments, such as depicted in FIGS. 2 and 3,as well as others, balance-thrust member 106 may be provided with aplurality of traction-facilitating elements projecting from plantarsurface 150, such as, but not limited to, spikes, teeth, cleats, ridgesand the like. Such traction-facilitating elements may be fixedlyconnected to, and/or releasably integrated with, and/or integrallyformed from balance-thrust member 106 by any conventional methods.Choice of construction materials for balance-thrust member 106 shouldhave sufficient hardness, as determined by conventional methods, toretain traction-facilitating elements and effectively transmit forcesfrom sole 100 to supporting surface and vice versa.

[0072] Front zone 146 of balance-thrust member 106 extends up to, and inselect embodiments, extends beyond, the phalanges distal margin of thefirst metatarsal bone. Front zone 146 of balance-thrust member 106 endsin a termination point 160, which may be in the form of tractionfacilitating members, such as spikes, teeth, ridges, grooves and thelike, depending upon the particular embodiment. Termination point 160may be variously located long the longitudinal axis (X-axis) of sole100. For example, FIG. 2 depicts a shoe designed for mid-to-longdistance sprinting and has termination point 160 at adownward-projecting angle and extending somewhat beyond the forwardperimeter of support base 158 and upper 10, but other embodiments, suchas a distance shoe and/or jogging shoe, may have termination pointextend even further beyond the forward perimeter of support base 158 andupper 10 and not have as pronounced a downward projecting angle. Medial154 and lateral 156 margins of balance-thrust member 106 generallyfollow the natural contours of the anatomical features of the foot. Aswith other aspects of the present invention, plantar surface 150 area ofbalance-thrust member varies with each particular embodiment. Forpurposes of example, select embodiments, such as in FIG. 2, lateralmargin 156 may define a more focused balance-thrust member, that is,delineate plantar surface 150 area of balance-thrust member 106 toencompass the first through fourth metatarsal-phalanges areas of thefoot, such that horizontal propulsive forces at toe-off are effectivelyfocused on the most relevant parts of the foot.

[0073] FIGS. 4A-C depict various embodiments of the present invention.As previously mentioned, systems and methods of the present inventionare variously configured to accommodate different types of running, suchas, but not limited to, long-distance running or jogging (FIG. 4A),intermediate distances, such as 1,500 m racing (FIG. 4B), mid-to-longdistance sprints, such as 400 m racing (described in detail above and inFIGS. 2 and 3), and short-distance sprints, such as 100 m racing (FIG.4C).

[0074] Kinesiological analysis of running has demonstrated differenttypes and speeds of running involve different biomechanics. During arunning cycle involving a heel-strike, such as jogging, various portionsof the foot undergo a number of movements and are exposed to variousforces. When foot-strike, that is heel-strike, is initiated, the foot isin supination and as contact progresses pronation permits partialabsorption of impact forces. As the foot transitions from mid-support totakeoff, resupination, or transfer to the lateral ball portion of thefoot occurs as the foot becomes a rigid lever. The continuous motiontransfers from lateral to the medial ball of the foot as the footaccelerates through toe-off. In contrast, during sprinting, the groundstrike occurs in the forefoot or metatarsal area of the foot and thepoint of impact tends to be under or slightly behind their center ofgravity. As a result, this form of running has less of the decelerationphase associated with heel-strike running and propels the body massforward more efficiently.

[0075] Systems and methods of the present invention provide a range ofembodiments to accommodate these biomechanical requirements. In general,the angle of displacement is directly related to the type and speed ofrunning. In short, the faster the running speed, the higher the angle ofdisplacement, as depicted by pivot zone profile 170, and the moreproximal to the toe region 126 the pivot zone 140 is oriented. Thesesalient points are most clearly illustrated by contrasting respectivefoot-strike 102′, 102′″, angular displacement 104′, 104′″ andbalance-thrust members 106′, 106′″ in a distance-running embodiment(“running shoe”—FIG. 4A) versus a short-sprint embodiment (“sprintingshoe”—FIG. 4C). As clearly illustrated, the distance-running shoepresented in FIG. 4A has a more extensive foot-strike member 102′, withrear zone 114′ of foot-strike member 102′ extending to completelyencompass heel section 120, and is substantially thicker to moreeffectively absorb impact forces, whereas the embodiment designed forsprinting illustrated in FIG. 4C, has a limited foot-strike member 102′″with rear zone 114′″ of foot-strike member 102′″ extending from theforward section of the arch region 122 into the forefoot region 124.Foot-strike member 102′″ of the embodiment designed for sprinting isoriented to accommodate a running style wherein initial contact with thesupporting surface is predominantly in the forefoot area of the foot.Angular displacement member 104′ of the distance shoe has a lower pivotarea profile 107′ as compared to the angular displacement member 104′″of the sprinting shoe's pivot area profile 170′″. Additionally, angulardisplacement member 104″ with apex 172 for the running shoe has a largerradius in relation to angular displacement 104′″ with member apex 176for the sprinting shoe. This allows the sprinting to maintain a higherangle of displacement and faster rotation. Furthermore, balance-thrustmember 106′ of running shoe encompasses a greater surface area of toesection 126, and in some embodiments, front zone 160′ may extend beyondtoe section of upper, whereas, balance-thrust member 106′″ of sprintingshoe encompasses comparatively less surface area.

[0076] During a running cycle, as the initial foot-strike makes contactwith the supporting surface, there is a certain amount of supination andthe foot is slightly ahead of the center of mass, which serves tominimize deceleration forces and to preserve linear forward momentum.The talocalcaneal, or subtalar, joint plays a major role in convertingthe rotary forces of the lower extremity into forward motion. Inoperation, systems and methods of the present invention build upon thesenatural movements by assisting foot-strike to occur at a point under andbehind the center of gravity.

[0077] Following contact with the surface, the support phase isinitiated, wherein the runner's body mass is fully supported. As theknee flexes to absorb impact forces and support the runner, the ankleplantar flexes and the subtalar joint pronates, causing heel pronation.Heel pronation permits absorption of compressive shock forces, torqueconversion, adjustment to uneven ground contours and maintenance ofbalance. Eccentric tension in the posterior tibialis, soleus andgastrocnemius muscles cause deceleration of subtalar joint pronation andlower extremity internal rotation. Pronation reaches its maximum duringthis time and resupination is initiated to permit the foot to passthrough its neutral position at the midpoint of the support phase. Whenthe runner's center of mass is at its lowest position, a maximumvertical force is actively generated and transmitted to the supportingsurface by the muscles and is often referred to as the active verticalforce peak. This active vertical force peak typically reaches 2 to 8times body weight, depending on the speed of the runner. It is duringthe support phase that angular displacement member 104, and moreparticularly, pivot region 140, engage supporting surface, initiatingdisplacement of the runner's center of gravity. Systems and methods ofthe present invention serve to minimize the support phase, therebyconserving biomechanical energy by limiting energy lost to thesupporting surface. Furthermore, embodiments of the present inventionreduce shock and trauma to the runner by redirecting gravitational andinertial forces into linear momentum.

[0078] The support phase continues until the heel begins to rise intotakeoff during the recovery phase. Generally speaking, the recoveryphase is the stage of running in which muscular tension exerts verticaland horizontal forces to the support surface to propel the runnerforward. During this time the foot converts from a shock-absorbingstructure to a rigid lever for forward propulsion, which is largely dueto changes in position of the subtalar and midtarsal joints, and inparticular, supination of the subtalar joint. As the knee joint extends,the lower extremity rotates externally, the calcaneus inverts, themidtarsal joint locks, and the foot becomes a rigid lever. Thepropulsive force is a thrust backward and downward resulting from acombination of hip extension, knee extension and ankle plantar flexion.During the recovery phase, the rotational movement of the runner's footundergoes a second rotational movement as the runner rolls throughangular displacement and balance-thrust members 104, 106, respectively,incurring greater angular acceleration and thereby further displacingthe runner's center of gravity forward and translating gravitational,inertial, ground reaction, and muscular tension forces into linearmomentum.

[0079] These principles are more clearly presented in FIGS. 5A-D, whichillustrate the correlation of a foot cycle, herein defined as being frominitial foot-strike to angular displacement point, to angle 2 ofredirection of energy into maximum linear momentum. In general, theangle 2 of displacement required for maximal redirection of energy isdirectly related to the type and speed of running and the faster therunning speed, the greater the angle of displacement becomes. Forexample, embodiments designed for short-distance sprints, such as a 100m race (FIG. 5A) have a comparatively low foot cycle radius (r), whereasembodiments designed for long-distance running (FIG. 5D) have arelatively large foot cycle radius (r′″). Furthermore, foot cycle radius(r) is inversely proportional to the angle 2 of redirection of energy.In other words, embodiments designed for short-distance sprinting (FIG.5A) require a larger angular displacement profile 170.

[0080] Further example sole units according to the present invention areillustrated in FIGS. 8-17.

[0081]FIG. 8 generally shows the plantar side of a sole unit 811 formedof a rigidifying element of a substantially rigid nature, such as asubstantially rigid plate 813, that may be disposed under at least aforefoot of a wearer. The sole unit is intended for use in a left shoe,as are all other sole units of FIGS. 8-17.

[0082] As used in this document, “substantially rigid” means at leastrigid enough to facilitate a forward pivoting about the sesamoidal linewhile maintaining the sesamoid apparatus elevated relative to theportion of the foot that is forward of the sesamoidal line.

[0083] Preferably, the rigidifying element 813 extends between at leastthe sesamoidal line 817 and the balance-thrust line 806. The rigidifyingelement provides a platform for facilitating the digitigrade stance androtation about the sesamoidal line. Preferably, it should be contouredon the top and/or bottom surface to conform to the foot and/or tofacilitate placement of the foot in the digitigrade stance to providerotation about the sesamoidal line, in conjunction with the angulardisplacement member. The rigidifying element may also extend rearward ofthe sesamoid line 817 to the heel. In addition to plates, therigidifying element may be in the form of elongated bars, rods, fibers,and other such elements that are capable of creating a substantiallyrigid zone spanning between at least the sesamoidal line and thebalance-thrust line.

[0084] A rigidifying element may be made from carbon fiber, wood,fiberglass, nylon, plastics, metal, fiberglass, and other such materialsknown to persons skilled in the art.

[0085] The sole unit 811 includes an angular displacement member 804,that is preferably disposed substantially along or about the sesamoidalline. The angular displacement member 804 on sole unit 811 may be formedin a continuous line 817 or in one or more separate sections along orabout the sesamoidal line or a portion of such line. It may be astraight or curvilinear line, so long as some aspects coincide on orabout the sesamoidal line. For example, curvilinear aspects could follownatural flexural axes of the foot.

[0086] Notably, the angular displacement member 804 need only occupysuch points along or about the sesamoidal line to enable the foot topivot around the line. The angular displacement member may be made ofany material that will provide such pivoting in relation to adjacent orsurrounding material.

[0087] The sole unit 811 also includes a balance-thrust member 806. Asearlier noted, a balance-thrust member is disposed along a line forwardof the angular displacement member, and it is defined preferably by thefirst distal phalange and the third distal phalange. The balance-thrustmember is disposed at the forward end of the pivoting zone andstructurally acts to interrupt and counterbalance the rotational effectprovided through the angular displacement member.

[0088]FIG. 9 is a cross-section of sole unit 811 taken along line 9-9 inFIG. 8. It shows that angular displacement member 804 and balance-thrustmember 806 are projecting away from the surface of plate 813. Therelative height of the angular displacement member raises the sesamoidapparatus and enables the wearer's foot to pivot around the sesamoidalline.

[0089] Angular displacement member 804 and balance-thrust member 806 maybe made of a firm or substantially rigid material or semi-resilientmaterial or have a structure that imparts such properties. In any case,the angular displacement member should be configured to allow smooth andeven pivoting action. In the case of the balance-thrust member, itshould have sufficient firmness or resistance to serve as a check on therotation imparted by the angular displacement member.

[0090] In FIG. 8, the angular displacement member and balance-thrustmember are shown as discrete elements associated with sole unit 811. Theangular displacement member and balance-thrust member may be directlyaffixed to other elements of the sole unit but do not necessarily needto be. For example, they may be free of any direct connection to othermaterial but held in position by adjacent, abutting material, such asmidsole. Alternatively, the members may be integrated into a sole unithaving a unitary or monolithic structure. For example, using knownmolding techniques, a sole unit may be formed to integrally include therigidifying member, angular displacement member, and/or balance-thrustmember. In further illustration, the angular displacement member and/orbalance-thrust member could be formed in a monolithic or unitary pieceof material, with the members having a higher durometer or density orthickness relative to adjacent material such that pivoting andcounterbalancing may occur.

[0091] The sole unit of FIG. 8, and the other figures, may include oneor more layers or regions of an in-fill material, such as a cushioningmaterial 815 that the displacement member and/or balance-thrust memberare adjacent to, covered with, or otherwise integrated with, in whole orpart. Such materials may help provide a pivotable configuration for theangular displacement member 804. The in-fill may extend to the heel,depending on comfort needs and the type of the athletic event for whichthe shoe is intended. From the teachings herein, persons skilled in theart will be able to determine appropriate coverage and thickness forparticular applications without undue effort.

[0092] In one example embodiment, a shoe includes an upper associatedwith a substantially rigid plate, such as a thin, contoured carbon fiberplate 813. A standard foam or rubber midsole is disposed under theplate. An angular displacement member is disposed along or about asesamoidal line. The angular displacement and the balance-thrust memberare integrated into the midsole. A standard rubber outsole is disposedunder the midsole. The angular displacement member and balance-thrustmembers are made of a firmer material than the relatively compliantmaterial of the midsole. The angular displacement member in associationwith the substantially rigid plate places the foot in a digitigradestance with rotation around the sesamoidal line.

[0093]FIG. 10 shows another possible embodiment of a sole unit 1011according to the principles of the present invention. A plurality ofsubstantially rigid discrete elements are disposed along the sesamoidalline and/or the balance-thrust line to provide the angular displacementmember and/or the balance-thrust member. In one variant of thisembodiment, the discrete elements are a plurality of spikes 1021 ortraction elements for a running track surface. This embodiment isotherwise generally similar to the sole unit of 811. Preferably, theangular displacement member and balance-thrust member are disposed on asubstantially rigid plate 1013. FIG. 11 shows a cross-section of thesole unit of FIG. 10 taken along line 11-11 in FIG. 10. As illustratedin FIG. 11, the discrete elements 1021 project downwardly from the soleunit so that they support the wearer in a digitigrade stance. Plate 1013unit may also extend close to or all the way to the heel, consistentwith conventional track shoe design. In other possible embodiments, thelength of the sole unit may cover the foot to a lesser degree dependingon the intended purpose of the shoe. The sole unit 1011 may optionallyinclude some cushioning material or other in-fill material 1015, asdescribed above.

[0094]FIG. 12 shows a plantar view of another possible embodiment of asole unit 1211 according to the principles of the present invention. Thesole unit 1211 includes a first substantially rigid plate 1213A, whichis disposed generally on a lateral side of the sole unit. A secondsubstantially rigid plate 1213B is disposed on a medial side of the soleunit. The plates are adjacent or closely separated along an arcuate line1217 that at least in part coincides with the sesamoidal line. Theplates mass material to define the angular displacement member 1204 andbalance-thrust member 1206, as indicated in FIG. 13, which is asectional view of sole unit 1211 along line 13. For a wearer having anormal foot strike profile, the foot would normally land on the heel androll to plate 1213A and then to plate 1213B. Accordingly, plate 1213A ispreferably adapted for cushioning and plate 1213B is relatively firmerfor propulsion.

[0095]FIG. 14 shows a sole unit 1411 with an angular displacement member1404 comprising a plurality of generally parallel rib elements 1422 thatare oriented substantially parallel to the longitudinal axis of the soleacross the sesamoidal line. The rib elements may be substantially rigid,or may be less compliant than adjacent rearward or forward materials, tofacilitate rotation about the sesamoidal line. FIG. 15 is sectional viewof sole unit 1411 taken along line 15-15. As illustrated in FIG. 15, theribs 1422 project downwardly from the sole unit so that they support thewearer in a digitigrade stance. The ribs also have an arcuate profile tofacilitate pivoting. A fill-in material 1415 may be included in the soleunit, as per other embodiments.

[0096]FIG. 16 shows a sole unit 1611 with a laterally disposedbalance-thrust member 1606 on the lateral and/or medial side of a soleunit. This location may be in addition to or an alternative thebalance-thrust members of the earlier embodiments. The balance-thrustmember 1606 works in conjunction with an angular displacement member, asdescribed above. A laterally disposed balance-thrust member may be usedin shoes intended for lateral cutting movements, such as basketball,soccer, and tennis. FIG. 17 shows a cross-section taken along line 17-17of the sole unit 1611 of FIG. 16. Preferably, as in other embodiments,this embodiment of a sole unit has the balance-thrust member disposed ona substantially rigid plate 1613.

[0097] While the sole units of the foregoing embodiments may be shownisolated from an entire shoe or sole, from the following details,persons skilled in the art will be capable of integrating the disclosedsole unit into a complete shoe or sole using known techniques.

[0098] While in the foregoing specification this invention has beendescribed in relation to certain preferred embodiments thereof, and manydetails have been set forth for purpose of illustration, it will beapparent to those skilled in the art that the invention is susceptibleto various changes and modification as well as additional embodimentsand that certain of the details described herein may be variedconsiderably without departing from the basic spirit and scope of theinvention.

What I claim:
 1. A shoe having a sole unit, the sole unit comprising: arigidifying element disposed between at least a sesamoidal line and abalance-thrust line; an angular displacement member disposed at thesesamoidal line; and a balance-thrust member disposed at a balancethrust line, the angular displacement member and balance thrust memberbeing positioned and adapted so that when both members are in contactwith ground, the sesamoid apparatus of the wearer's foot is elevatedwith respect to the digits, placing the wearer in a digitigrade stanceduring at least a substantial portion of the support-propulsive phasesof the gait cycle.
 2. A shoe according to claim 1 wherein therigidifying element comprises a plate.
 3. The shoe according to claim 1wherein the plate has a contoured surface to facilitate rotation of thefoot about the sesamoidal line.
 4. The shoe according to claim 2 whereinthe plate comprises carbon fiber.
 5. The shoe according to claim 1wherein the plate extends to a heel portion of the sole unit.
 6. Theshoe of claim 2 wherein the angular displacement member comprises asemi-deformable material and has relatively less compliancy andresiliency than that of a rearwardly adjacent foot-strike member.
 7. Theshoe of claim 2 wherein the angular displacement member comprises anessentially non-deformable material.
 8. The shoe of claim 1 wherein theangular displacement member comprises a rigid material that is disposedalong a sesmoidal line and has relatively less rigid material disposedforward or rearward of the sesamoidal line.
 9. The shoe of claim 1wherein the angular displacement member comprises a plurality of ribelements oriented along the sesamoidal line to facilitate fore-aftpivoting of the foot of a wearer about the sesmoidal line.
 10. The shoeof claim 1 wherein the sole unit includes a balance-thrust memberdisposed generally on a lateral or medial side of the sole unit in aforefoot portion of the sole unit.
 11. A method of making a shoecomprising: providing a sole unit, the sole unit comprising: arigidifying element disposed between at least a sesamoidal line and abalance-thrust-line; an angular displacement member disposed at thesesamoidal line; and a balance-thrust member disposed at a balancethrust line, the angular displacement member and balance thrust memberbeing positioned and adapted so that when both members are in contactwith ground, the sesamoid apparatus of the wearer's foot is elevatedwith respect to the digits, placing the wearer in a digitigrade stanceduring at least a substantial portion of the support-propulsive phasesof the gait cycle; providing an upper for covering at least a portion ofa top surface of a wearer's foot; and physically associating the soleunit with the upper.
 12. A sole unit for a shoe comprising: arigidifying element disposed between at least a sesamoidal line and abalance-thrust line; an angular displacement member disposed at thesesamoidal line; and a balance-thrust member disposed at a balancethrust line, the angular displacement member and balance thrust memberbeing positioned and adapted so that when both members are in contactwith ground, the sesamoid apparatus of the wearer's foot is elevatedwith respect to the digits, placing the wearer in a digitigrade stanceduring at least a substantial portion of the support-propulsive phasesof the gait cycle.
 13. A sole unit according to claim 12 wherein therigidifying element comprises a plate.
 14. A sole unit according toclaim 13 wherein the plate has a contoured surface to facilitaterotation of the foot about the sesamoidal line.
 15. A sole unitaccording to claim 12 wherein the plate extends to a heel portion of thesole unit.
 16. The shoe of claim 1 wherein the angular displacementmember comprises a section of midsole material and the rigidifyingelement.
 17. The shoe of claim 1 wherein the angular displacement membercomprises a section of midsole material and the rigidifying element, thesection of midsole material being disposed substantially above therigidifying element.
 18. The sole unit of claim 12 wherein the angulardisplacement member comprises a section of midsole material and therigidifying element.
 19. The shoe of claim 12 wherein the angulardisplacement member comprises a section of midsole material and therigidifying element, the section of midsole material being disposedsubstantially above the rigidifying element.
 20. The shoe of claim 12wherein the angular displacement member comprises a section of midsolematerial and the rigidifying element, the section of midsole materialbeing disposed substantially above the rigid plate and the sole unitincluding a section of outsole materials disposed below the rigidifyingelement.
 21. A shoe having an upper and a foot supporting member, thefoot supporting member comprising: a substantially rigid member having adorsal surface and a plantar surface; the plantar surface having anangular displacement member comprising a convex portion and a forwardlydisposed balance-thrust member comprising a concave portion, the concaveportion extending forward past the tips of the digits and terminatingdistally at a downwardly projecting balance-thrust member, the convexportion and the concave portion cooperating to accommodate the wearer ina digitigrade stance during at least a substantial portion of thesupport-propulsive phases of the running cycle.
 22. A shoe according toclaim 21 further comprising the plantar surface convex includes a curvedangular displacement surface below the sesamoid apparatus of the firstmetatarsal phalangeal joint and defining a first axis of rotation of thefoot.
 23. A shoe according to claim 22 further comprising thebalance-thrust member defining a second axis of rotation of the footforward of the wearer's foot.
 24. A shoe according to claim 22 furtherwherein curved angular displacement surface and balance thrust memberare positioned so that when both are in contact with ground, thesesamoid apparatus is elevated with respect to the digits.
 25. A shoeaccording to claim 21 further comprising a foot strike member adjacentthe convex surface.
 26. A shoe according to claim 21 further comprisingthe dorsal surface including a concave portion having a curvatureselected to support the digits of the wearer's foot in a dorsiflexedposition relative to the metatarsals.
 27. A shoe having an upper and afoot supporting member, the foot supporting member comprising: asubstantially rigid member having a dorsal surface and a plantarsurface; the plantar surface having a convex portion and an adjacentconcave portion, the concave portion extending forward past the tips ofthe digits and terminating distally at a downwardly projectingbalance-thrust member; the plantar surface convex portion including acurved angular displacement surface below the sesamoid apparatus of thefirst metatarsal phalangeal joint and defining a first axis of rotationof the foot; and, the balance-thrust member defining a second axis ofrotation of the foot forward of the wearer's foot.
 28. A shoe having anupper and a sole member, the sole member comprising: a dorsal surfaceand a plantar surface; the plantar surface having an angulardisplacement member and a forwardly disposed balance-thrust member, theangular displacement member and the balance-thrust member cooperating toaccommodate the wearer in a digitigrade stance during at least asubstantial portion of the support-propulsive phases of the runningcycle.
 29. A shoe according to claim 28 wherein the angular displacementis disposed at least in part below the sesamoid apparatus of the firstmetatarsal phalangeal joint and defining a first axis of rotation of thefoot.
 30. A shoe according to claim 28 wherein the angular displacementhas a convexly curved surface, the angular displacement member and thebalance-thrust member being positioned so that when both are in contactwith ground, the sesamoid apparatus is elevated with respect to thedigits.
 31. A shoe according to claim 28 further comprising a footstrike member rearwardly adjacent the angular displacement member.
 32. Ashoe according to claim 28 wherein the shoe includes a sole membercomprising a substantially rigid material having a plantar surface; theplantar surface having the angular displacement member disposed thereon.33. A shoe according to claim 28 wherein the shoe includes a footsupporting member comprising a substantially rigid member having adorsal surface and a plantar surface; the plantar surface having theangular displacement member disposed thereon and the dorsal surfaceabove the plantar surface having a concave shape for receiving at leasta portion of the forefoot.
 34. A sole member for a shoe comprising: afoot strike member, an angular displacement member, and a balance-thrustmember, the aforesaid members cooperating during at least a portion ofthe support-propulsive phases of the running cycle to facilitate linearmomentum, the angular displacement member being positioned at least inthe metatarsal area of a foot and substantially underlying at least anarea under the sesamoid apparatus of the first metatarsal, thebalance-thrust member being located forward of the angular displacementand is at least in an area underlying or ahead of the distal phalanges.35. The sole member of claim 34 wherein the dorsal surface has a convexshape above the angular displacement member for receiving at least aportion of the forefoot.
 36. The sole member of claim 35 wherein theangular displacement member comprises a semi-deformable material and hasrelatively less compliancy and resiliency than that of the foot-strikemember.
 37. The sole member of claim 34 wherein the angular displacementmember comprises an essentially non-deformable material.
 38. The solemember of claim 34 wherein the angular displacement member comprises asemi-deformable material that has relatively less compliancy andresiliency than that of the foot-strike member.
 39. The sole member ofclaim 38 wherein the angular displacement member comprises anessentially non-deformable material.